There is a new UI specification for Tools-Options, which defines how the editor related panels for particular languages
should be rearranged. Please see http://ui.netbeans.org/docs/ui/options2/ for more details.

I'd like to ask - what exactly will be the per-language UI for Formatting and Hints?
I would expect that for the formatting options, each language will be able to provide UI for formatting options specific
to this language (JPanel that would be displayed under the combo box). If a language does not provide any UI, the
infrastructure will provide a fallback UI - something like the current UI under Editor | Indentation options.
For the hints, I assume there would again be a per-language UI, but if the language does not provide any implementation,
it will not appear in the language combo box at all.
Is this a correct assumption? Is this the desired solution? (This part is not specified in the UI spec). Thanks.

Yes, something along these lines.
There are several formatting settings that are common to all languages - those exposed in the current Editor ->
Indentation panel. So far these settings have been managed 'together' - meaning that changing them in the UI modified
those settings for __all__ mimetypes. I think we should keep this option otherwise it will become really hard to change
for example 'Number of spaces per indent' for all languages available in the IDE. The combo box makes sense for big
languages, which provide a lot of fine grained formatting settings, but makes only a little sense for common indentation
settings like tab size, indent size, right margin, etc, because typically users want to adjust those at once for all
languages.